The
Gormenghast trilogy.
I've only read the first book, but it is highly memorable. Every so often I think about it and kick myself for not reading the other two books. I must get around to it. (Actually, I just might want to read the first one over again.)
It's a kind of "low" fantasy, if there is such a thing. It has no magic, and there are elements of surrealism and the gothic. It has a wonderful claustrophobic sort of feel to it. A very believable fantasy world. The characters are engaging, and the story is offbeat. It was written around the same time as
The Lord of the Rings.
That said, I'd like to find more like it. I can't read most fantasy I've looked at lately. I've been ruined by studying literature at university.